Once manufacturing is complete, the cables are spooled into large tanks and then tested for water resistance and other parameters.

The cable system includes large, missile-shaped repeaters to boost the signal across the ocean. This 9,000-kilometer-long cable is being created for the transpacific FASTER cable (BETWEEN JAPAN AND THE U.S.) that’s backed by Google.

Once it’s ready, the cable is sent out along rollers to a cable ship docked by the factory.

This is the René Descartes, owned by French telecom firm Orange. Dozens of workers are needed to load the cable, as well as the large repeater units, onto the ship.

Once inside, the cable is fed into three tanks below the main deck, and they are huge, hot and humid. The cable has to be looped very carefully to prevent tangles.

Back up on the main deck, we can see a few of the tools needed to lay the cable. About the size of a small house, the plow Elodie is used to dig trenches on the coastal seabed, where the cable needs to be buried for protection from anchors iand nets.

Next up is the Hector 6, an ROV that can work up to 2,000 meters below the surface of the ocean. It has caterpillar tracks for propulsion, jets to help bury the cable in its trench, as well as robotic arms to manipulate it.

On the bridge, engineers can control the arms with small-scale replicas, as well as joysticks to control the ROV and plow.

It takes a light touch, and a lot of patience, to install a cable all the way across the Pacific.